Mack Hansen claimed a first-half hat-trick to set Ireland on course for a record 46-19 win over his native Australia in Dublin.
Canberra-born Hansen, who started at full-back for the first time at Test level, celebrated his return from a foot injury by crossing three times in the opening 28 minutes to delight a capacity Aviva Stadium crowd.
Second-half scores from Caelan Doris, Ryan Baird and Robbie Henshaw ensured head coach Andy Farrell again came out on top against former Ireland boss Joe Schmidt.
Australia trailed by just five points at the break following converted tries from Len Ikitau and Fraser McReight and claimed a late consolation through Billy Pollard.
But Ireland were deserved winners ahead of completing their autumn campaign at home to world champions South Africa next weekend.
Fly-half Sam Prendergast kicked seven points, including a drop goal, for the dominant hosts, before his replacement Jack Crowley slotted a further nine.
Farrell led the British and Irish Lions to a 2-1 series victory over Schmidt's Wallabies in the summer following Ireland's 22-19 victory over the same opponents last November.
His side - showing nine personnel changes from last weekend's disjointed 41-10 success over Japan - were rewarded for a rapid start on a soggy Saturday evening.
Hansen crossed twice in the opening 11 minutes, diving under the posts after being teed up by Stuart McCloskey following a quick-tap penalty before collecting a Prendergast pass to register a carbon-copy effort.
Australia, who suffered a shock defeat to Italy last weekend and had lost five of their previous six Tests, responded when centre Ikitau beat Prendergast to barrel over.
Hansen, whose mother hails from Cork, then further punished his homeland, powering across the line wide on the right after Prendergast's crossfield kick was spilled backwards by Tommy O'Brien.
Yet the Wallabies were only 19-14 behind at the interval as flanker McReight crashed over in the final play of the half, with fly-half James O'Connor adding his second conversion.
Ireland had struggled to set pulses racing with their performances this month and would have been eager to secure greater control of the scoreboard.
After hooker Dan Sheehan was held up on the line, Prendergast nailed a drop goal from distance before providing a sumptuous crossfield kick assist for O'Brien, only for the score to be disallowed for a knock on in the build-up.
Crowley - on in place of the impressive Prendergast - slotted a penalty to stretch the score to 25-14.
Captain Doris then bulldozed over at the end of sustained pressure, with Crowley adding a tricky conversion, before Australia were left to play the final 10 minutes a man down after replacement lock Nick Frost was sin-binned for a high tackle on Tom Clarkson in the build up.
Despite the Wallabies' numerical disadvantage, replacement hooker Pollard went over to reduce the deficit.
But Ireland twice responded to seal an emphatic, six-try victory, with Baird crashing over before Henshaw raced clear down the left after being released by a sensational kick from Jamison Gibson-Park.
PA
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